flue liner

steve215

Hi, we had a stainless steel flue liner and multifuel stove fitted last year.
Unfortunately the chimney pot cracked soon afterwards and the guy came back and changed it, stating that it must have been a flawed pot from the builders yard. While he was changing it I noticed that the flue liner could not be seen above the brick section of the chimney stack. The pot has cracked again and when I look on the internet the Euroheat website illustrates on page 22 of their very comprehensive booklet on chimneys that the flue liner should extend the full length of the chimney, including to the top of the pot and the cowl should be fixed to the liner on the top. Although there is no explanation on the Euroheat document as to why the liner should extend the full length, including the pot, it seems to me that it is for insulation purposes to reduce thermal shock if it suddenly rains onto a hot chimney?
The guy who did the job is telling me that it is not important to have the liner extending above the chimney brick section and that my cracked pot is due to not burning smokeless fuel. Is he right or has he done the job wrong and should have fitted the flue liner to the top of the pot?
If he has done it right then what is the reason Euroheat show it done the other way?
Thanks

shane0007

Liner must go the whole length of the flue & terminated with a closure plate & cowl. Otherwise the liner is not lining the flue! If it is not attached to the closure plate, it can slip back into the flue, leaving unprotected liner which maybe in disrepair. It also provides a weakness at the joint between the two & potential issues can arise at this point.

If your installer tells you if it fine, ask him to obtain that in writing from the flue liner manufacturer & give the letter of authorisation to you for your records & any potential insurance claims that may arise in the future.

Me thinks he will not be able to provide this letter and install the flue correctly, as manufacturer spend fortunes on writing installation manuals. Can you imagine opening said page 22 of the extensive manual & you found it to only read "It'll be grand!"

steve215

Thanks Shane

I forgot to mention that we live in a bungalow and that the effects of any thermal shock would be greater as the pot is nearer to the heat source.
I was trying to find if the need to have the liner go all the way to the top was part of the building regulations but I can't see that it is. What do you reckon?

What about HETAS?
I have a certificate that states it's a HETAS compliant installation. I have had no dealings with them in the past.

Also, what about the comment that the fuel is causing the pot to crack. Ever heard of that one?

Thanks

Steve

DenisCork

Although Hetas is considered best practice in this part of the world it's Irish building regs that count here. Your liner should go all then way to the top of the pot and insulated all the way up. Personally I don't like closure plates as I think they're a bit flimsy and not fully waterproof which is a bit of a problem as vermiculite is very absorbent. I cut the liner slightly higher than the top of the pot and flaunch between the pot and liner with waterproofed mortar, topped off with a rain cap. If the insulation is filled in fully the liner has nowhere to go.

I'd be interested to know where the liner stops. Chimney fires can crack pots.

shane0007

It will be a manufactacturer's installation instruction rather than a building regulation, although their maybe a typical installation technical guidance document available.

I would contact the manufacturer for advice.

DenisCork

shane0007 wrote: »

It will be a manufactacturer's installation instruction rather than a building regulation, although their maybe a typical installation technical guidance document available.

I would contact the manufacturer for advice.

I'd always agree with manufacturers instructions, but in the case of a closing plate they're a flimsy quick fix for installers.

I was called to do an installation recently, the stove shop sold 2 separate lengths of flexi to make up 9 metres. They also supplied a jointing piece made from stainless steel with 2 male ends. Some manufacturer thinks this is ok.

shane0007

MI's can only be followed as they are the only parameters that have been tested under laboratory & EN conditions.

Closure plates are generally cemented in so they should be very secure & rigid. I suppose on their own & if not cemented in, they would appear very flimsy.

steve215

Surely a piece of pipe is a piece of pipe if it of the same specification stainless steel and the manufacturers instructions should all be the same?

I live in Kent and here there seems to be a difference of opinion according to who you speak to. Some chimney sweeps are saying that the pipe should go to the top of the pot, others say it's OK to have it stop at the top of the stack!

I would have thought that something as serious as a potentially cracked pot (falling down on someone) caused by lack of insulation and subject to thermal shock from rain should be covered in the regulations and not be left to manufacturers to say how their pipe should be fitted. Let's face it they make pipes, not fit them.

steve215

OK guys, thanks for advice do far.

Got an independent inspector coming next week with a camera probe
asked the original installer for the manufacturers details of the pipe and will contact them for further MI on the pipe.


I paid for the top quality 904 double skinned version. Let's hope that's what have!

I also looked on Utube for some guidance on how a flue liner should be fitted and found this ....
http://www.youtube.com/watch?v=RcVxKqkcCMc

Looks like I am not the only one to have a liner installed that stops at the top of the stack, but note the many comments!

Can of worms being opened springs to mind.

I am not a great lover of regulation, but maybe this is an area that needs some as there seem to be so many differents of opinion that it's scary

shane0007

If you are in Kent, UK, you have excellent regulation over solid fuel. HETAS will be acceptable standard of practices, but that will be just an interpretation of the actual regs. A bit like OFTEC & the regs.

You also have an excellent Building Control that will act on your behalf & sort out any installer errors, so if you are not happy with the outcome, they would be your first port of call, contactable in your LA office.

steve215

Problem is Shane that the liner going to the top of the pot doesn't appear to be a requirement of the building regulations, so although they and HETAS might be active in this area I don't expect they will act if it's not a contravention. Some installers here seem to be saying it's OK to have the liner stop below the pot and others say it isn't.

shane0007

You need to forget about what installer's views are because they are only views, their views & opinions differ.
Regs are a minimum but always manufacturer's instructions will over-ride unless manufacturer's instruction are less than regs, but they never are.
If MI's are stronger than regs, it's the MI that will be the minimum requirement.

So, you need to get clear definition from the manufacturer of the actual flue that has been installed in your home and you need to get it from the horse's mouth.